“The Earth reminded us of a Christmas tree ornament hanging in the blackness of space. As we got farther and farther away it diminished in size. Finally it shrank to the size of a marble, the most beautiful marble you can imagine.” –James Irwin

With everything that goes on in this world, from our daily lives to concerns around the globe, it’s easy to forget just how vast the Universe is, and how small we all really are. You had so much fun playing with the Interactive Scale of the Universe tool a couple of weeks ago that I had to just give you a few things to ponder. We think of the Earth, our entire world, as a pretty large place. But let’s put this in perspective.

The entirety of our planet, immense in both size and mass, is tiny compared to the Sun. The Sun is 109 times larger in diameter, over 300,000 times more massive, and has sunspots bigger than our planet.

But in the context of the Milky Way, our Sun — and even the entire Solar System — pales in comparison.

Image credit: Brown, Trujillo, and Rabinowitz.

Our Sun, 1.4 million kilometers in diameter, has a Solar System that extends out beyond Pluto, to a distance of about 140 billion kilometers. That’s the distance to Sedna at its farthest point from the Sun, the most distant Solar System object ever discovered. But even that great distance is nothing when placed into the context of our galaxy.

Image credit: NASA / CXC / M. Weiss, Harvard-Smithsonian CfA.

Because the distance to Sedna is just 1.5% of one light year, meaning it takes light around five days to go from the Sun to Sedna. But our galaxy is 100,000 light years across, or about ten million times the diameter of our Solar System. And it ought to be. Our galaxy alone contains hundreds of billions of stars, most of which have solar systems not unlike our own.

But compared to the rest of what’s out there, our galaxy is terribly insignificant.

Although “only” about 250,000 galaxies are shown in the above image, the entire Universe is estimated to have at least hundreds of billions of galaxies, spread out over a spherical region about a million times larger in diameter than our galaxy is. In other words, you and everything you know resides on a tiny, wet rock nearly a million times less massive than the star that powers it, in a solar system one ten-millionth the diameter of our galaxy, which contains at least hundreds of billions of stars not so different from ours, in a Universe filled with hundreds of billions of galaxies, and maybe perhaps more.

You. Are. Tiny.

It also inspired me to dig up this old (2008) video, that helps put into perspective just how big the Universe is. Sometimes, pictures can’t do the same justice that a well-put-together video visualization can. And the Universe? It’s really, really, really big!

[Some of the numbers you just heard are known to be larger now; we now believe that practically all stars have planets (and there are even planets that have no stars), the number of stars in the Milky Way may be closer to 400 billion, and there may be — when dwarf galaxies are included — upwards of one trillion galaxies in the Universe.]

Remember how big this Universe is, and how tiny we all are. But despite all of this, we all get to be a part of it, here, on the most beautiful marble you can imagine.

Some people when I try to explain how tiny we are, are distressed and find it hard to accept the insignificance. I then try to explain to them how incredibly BIG we are too, when compared to say, an atom, or a proton, or a quark. We are trillions of times larger then the basic building blocks of everything, and the universe in turn, is trillions of times larger then us. It’s all relative!

Just remember that you’re standing on a planet that’s evolving
And revolving at nine thousand miles an hour.
It’s orbiting at nineteen miles a second, so it’s reckoned,
The sun that is the source of all our power.
Now the sun, and you and me, and all the stars that we can see,
Are moving at a million miles a day,
In the outer spiral arm, at fourteen thousand miles an hour,
Of a galaxy we call the Milky Way.

Our galaxy itself contains a hundred million stars;
It’s a hundred thousand light-years side to side;
It bulges in the middle sixteen thousand light-years thick,
But out by us it’s just three thousand light-years wide.
We’re thirty thousand light-years from Galactic Central Point,
We go ’round every two hundred million years;
And our galaxy itself is one of millions of billions
In this amazing and expanding universe.

Our universe itself keeps on expanding and expanding,
In all of the directions it can whiz;
As fast as it can go, that’s the speed of light, you know,
Twelve million miles a minute and that’s the fastest speed there is.
So remember, when you’re feeling very small and insecure,
How amazingly unlikely is your birth;And pray that there’s intelligent life somewhere out in space,
‘Cause there’s bugger all down here on Earth!

Zaphod had seen the whole universe stretching to infinity around him — everything. And with it had come the clear and extraordinary knowledge that he was the most important thing in it. Having a conceited ego is one thing. Being told by a computer is another.

Actually, we are much more significant than a speck of dust. In particulaar, our unique sense of wonder seems dependent upon both our size and complexity. We inhabit the sweet spot for size and complexity.

Yes the whale has a bigger brain than us; but it takes a bigger brain to run its huge body and a thought can get lost just travelling from one side of its brain to the other. As well, the bigger the brain; the greater the portion of the brain that is clogged up with wiring. So the the physics of physiology (as we understand it, yes a big assumption) say we inhabit a sweat spot (in terms of size and complexity) for existence of intelligence life. It may not be the only sweat spot; but it is the only one that we know.

Thus to be alive, aware and full of wonder it appears necessary to be cosmically tiny (as we are) and biologically/ neurologically complex as we are.

Think Popeye saying, “I yam what I yam.” A human being with trillions of cells with 90 per cent guests that make you, you, and as a wise old man once answered the question, “What is a human being?” A scum bag porter lifting and carrying microbes around his or her whole life and benefiting from the reciprocity of cellular interaction when all is well until life’s day’s end and the lights go out and immortal recycling occurs as star dust is recast into the ever changing world of the living or not. As the philosopher Kant once noted there are things we may never know. Getting a true grip on our place in the expanding universe and a real sense of proportion of vastness and how incredibly tiny we are as a part of the whole growing universe.

“It’s a great big universe, and we’re all really puny.
We’re just tiny little specks, about the size of Mickey Rooney.
It’s big and dark and inky,
And we’re all small and dinky.
It’s a big universe, and we’re not.”

And once you have determined how big the universe is, then realize that what we can detect only represents 5 percent of the total amount of “stuff”. The other 95 may be dark matter or dark energy that we can’t detect.